Saturday, October 8, 2011

Sun spider

A Solifugae (Class Arachnida, order Solifugae [=Solpugida]) from Nebraska.
Solifugae (a.k.a. -- sun spiders, wind scorpions, or camel spiders) are common to the dry places of the world. Western Nebraska is such a place. Even still, I was pleasantly surprised today when a fella from one of the local welding companies brought by the critter above. It was apparently roaming around the welding shop. Yep, 'normal people' might freak out upon someone bringing one of these into their office. An entomologist says, "that is so cool!"

I have seen these before in collections and as 'pets' in terrariums, but I've never had someone bring one in for an identification. Maybe you have already noticed that this animal doesn't look like your every-day spider. It isn't. They do belong to the same class as spiders, Arachnida, but they are in a different order, the Solifugae. There are a couple characteristics that make these critters stand out. The chelicerae are fashioned into a set of vertical pincer-like appendages that hang in from of a small set of eyes. Also, count the legs ... Spiders have 8 (4 pair) legs, but how many do you see here? If you counted 10, you were tricked. The first pair of leg-like appendages are not legs, they are enlarged pedipalps that help the sun spider feel around in the darkness where it prefers to hang out.

Our Nebraskan camel spider is only a couple inches long (not as fancy as some of the giant African solifuges). None-the-less, he is now a resident in an aquarium at the PREC entomology lab. Perhaps I'll provide some video of the critter in action in the near future. Hopefully I have some success in keeping it, I'm not doing such a great job with my Madagascar hissing cockroaches (although major kudos to my technicians for helping keep them limping along). If I'm successful at keeping our 'pet' solifuges alive, it is bound to generate interest in the school groups to whom we often speak. 

Saturday, September 24, 2011

A lot of gall...(and lame puns)

I got a call a couple days ago; hornets, bees, flies, and wasps "of all kinds" were descending on someone's burr oak. The caller told me that they were witnessing a phenomenon that they "had never seen before in their life". Entomologists (at least extension entomologists) get these kinds of calls with some regularity. The caller was reporting to me that their neighbor's burr oak tree had millions of kinds of Hymenoptera and Diptera moving about all over the acorns of the tree. 

Back in the lab... We now have a number of things happening; sugar beet harvest, sunflower rating, dry bean host resistance assays, potato harvest, wheat planting... you get the point. Yet, the caller was a little dismayed when I refused to drop everything and make the 20-minute trip out to his property to look at a burr oak full of hornets. After getting a short lecture about how so-'n-so back in the day would drop everything to come out whenever he called and how he, as a farmer, has the luxury of doing what he wants when he wants because he is his own boss, I requested that he bring a branch off of the tree into my office. He then remarked that he couldn't because he had wheat to plant... He also didn't seem to amused when I pointed out the irony of his apparent mantra of "doing what he wants when he wants". But I told him that I would look into it.

Yesterday... One of my two very observant technicians came in to my office and mentioned that he had seen a number of burr oaks in town exhibiting the same phenomenon. He also mentioned that we had a burr oak in the front of the PREC, again in the same situation. So, I grabbed my camera, headed out, and the learning began. I saw the same thing that the caller had described -- wasps and hornets and flies roaming all over the "acorns" on the tree. So I did what any self-respecting entomologist would do and picked one of the "acorns" and licked it. Yep, sweet. I had mentioned to the caller that what he was observing on his burr oak was likely due to an infestation of insects (e.g., aphids or scales) secreting honeydew somewhere on the tree. I was partially correct. 

Yellow jackets frantically combing over cynipid galls on oak.
The investigation revealed that... The "acorns" that were observed, are not acorns at all but galls. These particular galls are produced by the tree around a bud that is infested with a tiny cynipid wasp. The wasp larva develops inside of the gall and as it feeds it secretes a honeydew that eventually oozes its way to the surface of the gall. In the fall of the year (after many of the flower plants in the area have finished blooming) many hornets in particular are attracted to the crystalline sugars on the surface of the green galls. If you split a gall open, inside you will find a single, tiny wasp larva. Apparently,  the hornets and bees do an exemplary job of defending the galls from gall parasitoids (even tinier wasps, sort of like this one) that attack the cynipid larva. In fact, a relatively recent study (I think in eastern Colorado) demonstrated that in areas where hornets and kin are less common, the parasitoids have a higher success rate at attacking the galls; therefore, the burr oaks are likely to succumb to the galling cynipids. 

Once the investigation ended... I contacted the caller. He was pretty anxious to know whether I had come out for a visit. I said that I had not, but that I had found other burr oaks in the area exhibiting the same thing. He was amazed that his situation was not unique and inquired as to what was causing it. I said, "aliens". He gave a half-hearted chuckle to my lame pun and then I went on to explain to him all of the details above. He was (again) amazed the diversity of the insect world and the wonders of nature.
How many hornets do you see in the photo above? Leave your answer as a comment under the link posted in Facebook. (Click on the photo to see an enlarged view.)

Monday, September 19, 2011

Sunflower


An adult sunflower receptacle maggot fly, Strauzia 
longipennis. The larvae feed on the white cork-like
material within the head (or receptacle) of the sunflower.
An adult black blister beetle, Epicauta pensylvanica
They pollinate flowers, consume grasshopper eggs as
larvae, can cause blisters if you touch them, and defoliate 
alfalfa. So, are they beneficial or pests?















Possibly a gray seed weevil, Smicronyx sordidus, on the left.
The newly-emerge adults are often found feeding on budbracts. 
They sometimes are destructive to sunflowers. 
There is also an ant (not sure of the species) on
the right. They are often beneficial and this one is feeding 
on some extrafloral nectar.  

A lacewing egg. Lacewings (Chrysopidae), are a 
natural predator of soft-bodied insects. They are 
natural enemies  of a number of soft-bodied insects 
and mites. Sunflowers can make a good substrate 
for egg laying.
I've been thinking a lot about sunflower as of late. Maybe because I recently harvested about an acre of the stuff. I decided to try my hand at a large sunflower insect control trial this summer. Now I'm in the midst of counting seeds for insect damage, taking hundredweights, and measuring yield. Next, we'll be splitting stalks and searching for injury from stalk-boring insects. All of this will be compiled into a year-end report that I will make publicly available either at the end of the year or very early next year. 

I have similar kinds of efforts with other crops (for example, I'm sure I have more acres devoted to sugarbeet research). However, Helianthus annuus is a bit different in that the abundance of insect life that you can find on (or within) just a single plant is pretty impressive. 

This abundance of insect life also places some particular challenges on their management. There are seed-boring and feeding weevils and caterpillars; flies and weevils that just feed on the head (just the bit that holds the seeds, also called the receptacle); caterpillars and leaf beetles that feed on the leaves; weevils and long-horned beetles that feed within the stalk; and scarab and click beetle larvae that feed on the roots. Ok, but these are just the insects that essentially "parasitize" the plant. Sunflowers have large flowers that attract many, many pollinating insects; from honey bees and bumble bees to beeflies and blister beetles and butterflies. In addition to flowers (usually a single, large flower per plant in cultivated sunflower), they also have extrafloral nectaries, particularly around the bud bracts, that provide a meal for beneficial insects such as adult parasitoids and ants. 

It is all of this shared habitat between beneficial insects and pests that make sunflowers (and some other crops as well) so difficult to manage by some conventional methods. Certainly, host plant resistance against the insects that we do not want could be one useful route to go. However, because of the tricky nature of the Helianthus genome, this might take a while. My colleague and friend, Jarrad Prasifka, was recently hired up in Fargo, ND at the Sunflower Research Unit. Perhaps he will come up with a creative solution in the near future. Until then, I'm working on trying to use chemical applications through an IPM program but using products that might allow application before the buds break open and before chemical applications might negatively impact good insects, such as pollinators. I guess we'll see if I'm successful. In the mean time, I've go a lot of sunflower seeds to count and weigh...




Wednesday, August 31, 2011

A female Argiope aurantia in a potato field.
A male (under side) Argiope aurantial in a potato field.

Argiope aurantia, the garden spider or corn spider, is stirring up some concerns in the panhandle. We seem to have a bumper crop of these critters this year and some people are concerned about their safety with these 8-legged behemoths lurking around. They are pretty striking; the females are black and yellow with long, black legs, and a body about 1/2 inch wide and 1 and 1/2 inches long. If you have arachnophobia, I'm sure that these animals would send you into shock. However, don't panic, they are good critters to have. They are not poisonous to humans or pets, although a large number of them (and their webbing) can make scouting field crops a notably unpleasant experience. However, they are beneficial for (at least) a couple notable reasons: 1) One of their common names is "corn spider" and they can be a frequent occurrence in corn fields around this time of year. In Nebraska, we irrigate quite a few acres of cropland. Many of these acres use overhead irrigation systems. These systems are held up and moved across the land with tires. Tires leave tire tracks that can hold pools of water and these tracks can make great breeding habitats for Culex sp. mosquitoes -- the vectors of West Nile Virus. These mosquitoes can be quite common, particularly in western Nebraska. Although adult garden spiders probably prefer something bigger like grasshoppers, the smaller, immature spiders may help keep those pestiferous mosquitoes down. 2) A quick search on my favorite reference database reveals many, many papers concerning the protein, material properties, and potential application of this species' silk. So, although some of you may cry, "eeek" upon walking up on one of these critters, they may also be giving a lot of benefit to us in return.

Tuesday, August 9, 2011

We have some research going on in the lab to understand the potential of Trichograma ostrineae (a parasitic wasp) to control the western bean cutworm (a pest of corn and edible dry beans). These are very, very tiny native wasps that like to lay eggs inside of caterpillar eggs. There are other pest insects that they attack as well, such as the European corn borer. I have an intern from UNESP, Brazil that is helping me understand the parasitism efficiency of this parasitoid on corn and edible dry beans. Bellow is a short video I took of the tiny wasps moving about inside of a petri dish containing a corn leaf with western been cutworm eggs on it. The eggs are less than 1mm.

video

Thursday, August 4, 2011

The 2010 PREC Entomology Lab.

 Recently at the Panhandle Research and Extension Center, we had our UNL Expo. This is basically a showcase of all of the cool stuff that we are doing out in Scottsbluff, Nebraska. Henda Pretorius took the opportunity to organize a photo shoot and Gary Stone kindly took some photos. I had such an amazing crew helping out this summer that I thought it worth while to post a couple photos here of the folks that helped make a lot of work happen this summer.
From Left to right: Jeana Jenkins (UNL undergrad), Sarah Peters (UNL undergrad), Kyle Koch (MS student), Henda Pretorius (International scholar), Johan Pretorius (PhD student), Riley Smith (UNL undergrad), Nathan Faulkner (UNL undergrad), Fernanda Pelegrinotti (International intern, UNESP, Brazil), Susan Harvey (Technician), Rick Patrick (Technician), me. I need to credit the creative lay out of my photos on the wall to the undergrads -- nice job!

My graduate students working the PREC Entomology Lab booth.

Thursday, July 28, 2011

Dragonflies

Photo courtesy of Katie Bradshaw (SCB Citizen).
The past couple weeks I have received numerous calls and inquiries about dragonflies. It is common for adult dragonflies to make an appearance this time of year. The last couple years, there has been more rain than the 10-year average in the panhandle of Nebraska. Due to an increase in habitat and food, dragonflies have done well. In fact, they have done so well that some people are actually concerned about their large numbers. However, what some people do not realize is that dragonflies are predacious. Fortunately, they feed on pest insects that also benefit from all of the rain that we have had, such as, mosquitoes and biting flies. They scoop them out of the air with the long setae that coat their legs. So, you see, it's a natural phenomenon and could be considered a balanced ecosystem process that benefits us greatly through the reduction of disease vectors -- dragonflies provide ecosystem services.

Friday, July 8, 2011

Sometimes entomology can be a little herpetological...

Johan on the "Panhandle R&E Entomology Field Machine".
I have a graduate student doing some pretty cool work with root aphids and sugar beets. We were engaged in a round of aphid infestation in his sugar beet field plots today. However, earlier this week, we collected pitfall trap samples and noticed that they catch vertebrates as well -- tiger salamanders (n = 1) and toads (n = 2) so far. Yes, I too was surprised to find amphibians in a sugar beet field in western Nebraska. I wouldn't exactly describe the climate here as humid.

Sarah, with her awesome bullsnake handling skills.
An annoyed bullsnake.
Anyway, the amphibians seemed to almost force themselves through the funnels and into the cups of the traps. This is surprising considering that the funnel holes are about 1-inch in diameter and are supposed to keep larger vertebrates out. I have assumed that they are somehow after a short-term cool-off in the killing solution in the trap cups. However, maybe they are on the run from bullsnakes. So far, just one. But, kudos to my helpful student worker, Sarah, who bravely handled our reptilian loiterer. Johan, on the other hand, is not a big fan of snakes (and that isn't actually the reason he is on top of the "field machine"). I was just glad that it wasn't a rattlesnake.

Thursday, June 16, 2011

Dust. It isn't an insect, but I'm sure it affects them.

Ok. So, this isn't insect related, but this kind of weather certainly can have a major impact on crops and entomological studies. Most of the Midwest doesn't experience this kind of weather. However, extreme weather seems to define this region. The top image is a storm front that blew in today. Note the rather large wall of dust that is moving in with it. The bottom video shows the result as the front passed over. I would guess that there was about 15-20 minutes of nothing but dust before a drop of rain fell.

Thursday, June 2, 2011

'Miller moths" [continued]



The army cutworm moths (A.K.A., miller moths) continue their increase. Last night an extremely large number of them began settling in the North Platte Valley. Today I took some footage of me spooking the moths out from their resting sites under the overhang at the Panhandle Research and Extension Center. Sorry for the jittery video, I was taking the video with my phone.

Tuesday, May 31, 2011

'miller' moths


The army cutworm (Euxoa auxiliaris) flght has been producing a steadying flush of moths over the past month. Any day that provides a bit of sun and warmth, one can find these moths about. However, we have been quite cold and rainy for the last month as well. Therefore it is difficult to say whether or not we are experiencing a larger flush of moths relative to last year. On the others hand I do seem to be finding more of them in my garage, in windows, and in public restrooms (see photo) than last year. Perhaps this week, since it is supposed to get much warmer and be free from precipitation, may reveal the true abundance of what the locals call 'miller moths' this year.
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Thursday, March 31, 2011

Mountain pine beetles

The mountain pine beetle, Dendroctonus ponderosae, is native to the western United States. Like many of our pests (e.g., grasshoppers, army cutworms, Russian wheat aphids, etc.) in the High Plains and Rocky Mountain regions, these insects can go through outbreak periods. During the past couple years these regions have suffered from devastating numbers of this insect attacking pine trees. The symptoms can be easy to spot...
When the beetles enter a tree, the burrow they create results in the formation of a "pitch tube"; the results of tree sap exudate (see above). The above tree has been attacked many times and there are many exit holes in the pitch tubes. However, this sapping process is part of a tree's defense system and if the tree is healthy...

It will actually drive the insect out of the burrow, entrapping it and ejecting it from the tree (see above)...

A very healthy tree can defend itself well against numerous pine beetle attackers (see above). If you examine a pine tree with a few pitch tubes with beetles in them, there is a good chance the tree will survive that year's attack and some insecticidal treatments and tree-health improvements could save the tree. However, if a tree has many pitch tubes without any beetles, it is likely that the tree is not going to survive and should probably be removed.

Monday, March 14, 2011

Linnean games UNL

Our 2011 ESA Linnean Games team.
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Saturday, February 19, 2011

Bird Louse

This critter actually came into my possession on December 8, 2010. It is a bird louse. The Central High Plains has quite a large migration of waterfowl this time of year. I tried my hand at waterfowl hunting this year and discovered that it is pretty easy to find lice on ducks. This one was taken from a mallard. I honestly do not know what species this is; there are about 15 species of avian louse. Perhaps it is a species of Anaticola, as these are frequently found on ducks. These lice are not known to transmit any diseases to ducks, but I would guess that a heavy infestation might be irritating.

Wednesday, February 16, 2011

Not all mites are bad mites.

We maintain a sugarbeet root aphid, Pemphagus betae, colony in my lab. This insect is a pretty important pest of sugarbeets in my area and subterranean aphids are just kind of cool to study. Today, while going through our aphid colony, we found a predatory mite in the act (above). Fortunately for us, we have way more aphids than mites. However, wouldn't it be nice to have these established in the field and feeding on the root aphids attacking our crops? Combined with resistant varieties, these mites could be really beneficial. Maybe they already are beneficial and just have not been recognized as such. I have a student working on various aspects of beneficial insects in our soil. So, maybe in a couple years this mite might be recognized as an untapped resource. However, in the mean time, I just hope it doesn't crash my aphid colony!

Wednesday, February 9, 2011

Dermestids with a sweet tooth.


Seems like dermestid larvae (the adults are tiny beetles) like chocolate. I guess this chocolate bar was part of a long-forgotten bag of Halloween treats. Dermestids are scavengers, they'll feed on any dry plant or animal material; grain, flour or even skin. (*warning* Don't click previous link if you have a weak stomach.) I knew that some Beatles liked chocolate (i.e., Savoy truffle); however, I didn't know that beetles do too.

Monday, February 7, 2011

Mexican bean beetle resistance.


In the lab, at the moment, we are busy screening about 20 edible dry bean varieties, lines, and land races for resistance against the Mexican bean beetle.
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